ABSTRACT
Substance is the oldest topic of philosophical inquiry and it is one of the most entangled. Positive theories of substance explain the unification of these complexes by their connection with a special additional unifying element. The negative theories that reject substance hold that there is no more to the complexes in question than the collection of elements of which they are composed. The chapter argues that there are four quite distinct problems of substance whose solution has been obstructed by persistent failure to recognise the distinctions between them. The four problems are: individuation, identity, objectivity and the foundations of knowledge. Failure to recognise the distinctness of the four problems of substance has given rise to a number of confusions which have had a large and destructive influence. The chapter also presents an overview of the key concepts discussed in this book.
